EJB query language

EJB query language enables you to write queries based on entity beans without knowing the underlying relational schema.

An EJB query is a string that contains the following elements:

• a SELECT clause that specifies the enterprise beans or values to return;

• a FROM clause that names the bean collections;

• an optional WHERE clause that contains search predicates over the collections;

• an optional GROUP BY and HAVING clause; see the topic Aggregation functions.

• an optional ORDER BY clause that specifies the ordering of the result collection.

Collections of entity beans are identified in EJB queries through the use of their abstract schema name in the query FROM clause.

The elements of EJB query language are discussed in more detail in the following related topics.

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Subtopics

Example: Queries with EJB
FROM clause
Inheritance in EJB query
Path expressions
WHERE clause
Scalar functions
Aggregation functions
SELECT clause
ORDER BY clause
UNION operation
Subqueries
EJB query language limitations and restrictions
EJB query compatibility issues with SQL
Database restrictions for EJB query
Rules for data type manipulation in EJB query
EJB query: Reserved words
EJB query: BNF syntax
EJB spec and WebSphere query language comparison

 

Related tasks

Use EJB query